title: Secretome Analysis of the Pine Wood Nematode Bursaphelenchus xylophilus Reveals the Tangled Roots of Parasitism and Its Potential for Molecular Mimicry.
abstract: Since it was first introduced into Asia from North America in the early 20(th) century, the pine wood nematode Bursaphelenchus xylophilus has caused the devastating forest disease called pine wilt. The emerging pathogen spread to parts of Europe and has since been found as the causal agent of pine wilt disease in Portugal and Spain. In 2011, the entire genome sequence of B. xylophilus was determined, and it allowed us to perform a more detailed analysis of B. xylophilus parasitism. Here, we identified 1,515 proteins secreted by B. xylophilus using a highly sensitive proteomics method combined with the available genomic sequence. The catalogue of secreted proteins contained proteins involved in nutrient uptake, migration, and evasion from host defenses. A comparative functional analysis of the secretome profiles among parasitic nematodes revealed a marked expansion of secreted peptidases and peptidase inhibitors in B. xylophilus via gene duplication and horizontal gene transfer from fungi and bacteria. Furthermore, we showed that B. xylophilus secreted the potential host mimicry proteins that closely resemble the host pine's proteins. These proteins could have been acquired by host-parasite co-evolution and might mimic the host defense systems in susceptible pine trees during infection. This study contributes to an understanding of their unique parasitism and its tangled roots, and provides new perspectives on the evolution of plant parasitism among nematodes.
authors.affiliation: Graduate School of Agriculture, Kyoto University, Kyoto, Japan ; College of Bioscience and Biotechnology, Chubu University, Kasugai, Japan.
authors.forename: Ryoji
authors.initials: R
authors.lastname: Shinya
authors.forename: Hironobu
authors.initials: H
authors.lastname: Morisaka
authors.forename: Taisei
authors.initials: T
authors.lastname: Kikuchi
authors.forename: Yuko
authors.initials: Y
authors.lastname: Takeuchi
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Ueda
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Futai
mesh_terms: D000818:Animals; D019143:Evolution, Molecular; D020440:Gene Duplication; D022761:Gene Transfer, Horizontal; D015801:Helminth Proteins / Q000235:genetics / Q000378:metabolism; D018716:Molecular Mimicry; D009348:Nematoda / Q000235:genetics / Q000378:metabolism; D010935:Plant Diseases / Q000469:parasitology
chemical_list: D015801:Helminth Proteins